code: def exp4(x, c, a, b, alpha):
      return c - np.exp(-a * (x**alpha) + b)
  
imports: import scipy
  import logging
  import numpy
  import time
  from scipy import optimize
label_desc: Use image node_id 9 for calling a global function with example usage: exp4(x, c, a, b, alpha) and returns: unknown